Usually, when a document is created using a personal computer (PC), it is printed out on paper, the content is checked, and corrections are made. Oftentimes this correction process is made several times. There are also times when corrections and changes are made to a document created once. In such times, if the entire document is printed each time a correction is made, paper and printing time are wasted in printing the parts that have not been corrected. Thus, oftentimes only the changed parts are printed and replacement is done with respect to the printing result of the before-changed document. However, oftentimes it takes a lot of time and effort to designate the changed parts for printing only those changed parts (e.g., designating the parts by page numbers of the document to be printed, etc.) and to find and replace the corresponding places from the before-changed document.
In order to solve this problem, Japanese Laid-Open Patent Publication No. 2000-57129 proposes a method where printing data of a document before being changed are saved in advance, and when the document after being changed is to be printed, the printing data of the document after being changed is compared with printing data of the document before being changed, the difference is extracted, and only the printing data of the pages where there is a difference are transmitted to a printer and printed.
Japanese Laid-Open Patent Publication No. 10-316302 proposes a method where, after sorting information has been added to each page of a document and the document has been printed, a document sorting device is used, the added sorting information is read by the document sorting device, and sorting is conducted in accordance with the sorting information, whereby sorting processing desired by the user is realized.
Japanese Laid-Open Patent Publication No. 2002-251272 proposes a printing system where printing data of a document before being changed are saved in advance, the page numbers of parts to be changed are designated with respect to the saved printing data of the document before being changed, and only the printing data of those parts are replaced with printing data after being changed and are printed, whereby a printing result of the document after being changed can be obtained.
However, in the invention disclosed in Japanese Laid-Open Patent Publication No. 2000-57129, in order to obtain a printing result of the document after being changed, it is necessary for the user to manually conduct replacement with respect to the printing result of the document before being changed after the pages where there are differences have been printed. Also, because the user must search the document before being changed for the changed parts by pages or sheets of paper, it takes a lot of effort to identify the changed parts from the document before being changed when the number of pages in the document is large.
In the invention disclosed in Japanese Laid-Open Patent Publication No. 10-316302, it is necessary to add the sorting information to all of the pages of the printing result, and it takes a lot of effort in the creation of the document, at the time of printing and at the time of preprocessing for sorting.
In the invention disclosed in Japanese Laid-Open Patent Publication No. 2002-251272, because the user must search the printing result of the document before being changed for changed parts by pages or sheets of paper, it takes a lot of effort in order to identify the changed parts from the document before being changed. Also, in order to obtain a printing result of the document after being changed, it is necessary to print the printing data of the document after being changed including places where there are no changes, and there is the potential to needlessly consume paper in printing the places where there are no changes.